Emergency fuel control



Oct. 21, 1952 w. s. BOBIER, JR

' EMERGENCY FUEL CONTROL Filed April 20, 1948 52kg a 121 .38. 13 5i er Jr.

INV EN TOR.

Patented Oct. 21, 1952 e I UNITED STATES PATEN OFFICE EMERGENCY FUEL'CONTROL Wilfred Bobier, Jn, Grosse Pointe, Mich., as- I signor'to; George M. Holley and Earl Holley Application April 20, 1948, Serial. No. 22,037

This invention relates. to the supply of fuel to a power plant of the type in which fuel flow controls speed; for example, a gas turbine.

The object of thisinvention-is to transfer'from the normal fuel supply system to an emergency fuel supply system whenever the normal fuel supply system fails to maintain the selected fuel supply and speed.

' Fig. 1 shows the preferred form of my invention.

Fig. 2 shows a detail taken on plane 2-'-2 of Fig. l.

In Fig. 1 fuel enters the passage 58 from which it is, delivered to the turbine. through two fuel. pumpsthe primary pump 60 and the emergency pumpBZ. The primary pump 60 discharges the.

primary fuel through aflpassage 18,, into the primary governor I08, past. the check valve H0, along the passage I H to theoutlet H4 off-the gas turbinanot shown;

When the" .check. valve" H is closed and the, emergency check'valve. H2 'is open, fuel flows from the passage 58, through the emergency pump 62, along the passage I6, through thepassagecld. to the emergency governor Hi4 and check valve ,lll2." The'control levers I02 and I06 and. aspeed setting. cam 90 are all linked, together bylinkage l03'-l.ii5. v

a Claims. (01. LES-@363)? In. the position shown. the selector valve- [0- is,

shown in the; position. in which. the emergency 1 fuel pump. 62 is inactive. Thefuel. then flows from the emergency pump 62,, through the. pas,- sage 16 into thechamber 64; and, back through thefpassage 6,3 to; the passageSB.

During operation a rotating casing; 43 is. rotated by the shaft 4| which is driven by agas tur-- bine. This casing 43 carries a centrifugal weight:

25 which is supported by a spring 28- and reciprocates in' a cylinder 21. This casing 43 rotatesi nia; chamberiZ which communicates through a passage, l0, apassage T9; to the outlet 18 of the primary pump '60. This fuel, inthe' chamber I2 is: thus; at the highest pressure; developed." by the primarypump 6.0. I

. The pressure inthe pipe Hi9, connecting the primary governor I08 with the; primary-- check. valve ii 0 is. at a lower pressure than thefuelv in: the chamber l2. A passage l4 connects; therp'asvsag 1.0.9 .With thepassage. 1.9; in the center of the shaft 41;. The;passage |-9 isconnectedto;theport- 1. which, port is: controlled, by the valve 22.. Valve 2 2:; is; provided with; an; opening: in; its can.- ter 2 3.- When thespring ZBi'pushesthe' weight 26: a g t raisesgthe valve. 22; and admits. high press sure f elg throughgzthez passa e 24; and: port; 25;

. 3 2 through the passage 23 to the inner end of the cylinder 21, to the passage 41 and ports 42 and 48. Passage 23 communicates through the restriction 29 through passage 32, to the chamber 33 which is-to the right of a diaphragm 34. Chamber 30, located to the left of'the diaphragm 34, is subjected to the pressure in the chamber I 2.

The passages l4 and I9 also communicate with the cylindrical chamber I6, above and below the perforated piston valve 44-, which'is normally in the positionshown, that isto say, in the position in which the port 48 is closed whenever the tur bine is running; When the turbine is not run ning and when it is runningat extremely low speeds the spring 46 pushes the element 44' down,

causes the port 43 to open and thus the pressure diiierence between the chamber IS, the port 48 and chamber 33 becomes zero; i

A similar perforated piston valve 38 is pushed radially in towards the center by the spring so as to close the port 42 at all times except at extremely high speeds. Both sides of the element 38 communicate at all times with the high pressure fluid in the chamber l2. Normally the ele-- the radial port 52 which communicates with the" passage32in the center of" the flywheel 5?.

During acceleration, the flywheel 5'1 tendsto lag"behind' the casing 43'. This brings the port 52 in linewith the restrictiontliin' the casing 133, thus: forming a direct passage from the passage l9 through the restriction lii, through the radial passage 52 to the axial passage 32; Thus a bypass is opened around the valve 22 and restriction 29' but this bypass onl'yrem'ains open during acceler ation and closes the momentthatsteady" speed:

is: reached.

I cam engages with a perforated piston 3t which compresses a spring92 which engages with.

a piston 88'; the piston 38 engages with a spring 96., spring 96 engagesia valve 54', and valve 54. en"- gages, withthe diaphragm, 34. The chamber. 93,}

to'the left of the piston 88, communicates.through. a restriction with a passage 91' and with the chamber 33 to the' right of the diaphragm 34.

Valve 54. isylocatedbetweenthe:low pressureifiuid passageifiand passage-;.

A manually operated lever I I controls a valve I I6 in the passage 55 connecting the valve 54 with a chamber 68, to the left of selector valve 10. A

Operation The moment the emergency pump 52 and the primary pump 60 start to work the valve 54 moves to the right as pressure is delivered to chamber 30, on the left hand side of the diaphragm 34. Chamber 33 communicates through port 50 with the low pressure passages I4 and I9. Check valve I admits pressure from primary pump 60 to passages 'I8'I9-IU to chamber I2 and so to chamber 58 on the left hand side of selector valve III which compresses spring 69 and closes valve seat 51 and at the same time opens a path past valve seat I l.

During the actual start when the turbine is rotating at very slow speeds the spring 46 holds the valve 44 down so that port 48 remains open.

Port 48 being open chamber 33 is in direct com munication with the passage I4, that is, with the pressure downstream of the primary governor I08. Valve 54 is thus held in its inoperative position by the pressure on the upstream side of the primary governor I08.

Opening valve seat II permits the emergency pump 62 to discharge fuel freely through passage I6 past the valve seat I I, through passage 58 back to the fuel entrances to pumps 50 and 62. Valve seat II remains open at all speeds where the cam 95 does not impose sufficient load on springs 92 and 94 to open valve 54. During acceleration the piston 88 temporarily delays the application of pressure on the diaphragm 34 by means of the restriction 55 and chamber 93. Port 52 and two restrictions 55 and 29 decrease the pressure on the diaphragm 34 temporarily. Hence, the cam 90 can be rotated anti-clockwise to increase the speed without putting the mechanism into the emergency position, unless there is a failure to respond to the increase in speed called for within a reasonable interval of time.

If an emergency occurs so that the primary governor I88 fails to supply the fuel to produce the speed called for by the position of cam 90 and of lever I06 then the weight 26 is pushed radially in by spring 23 and high pressure is transmitted from primary pump 65 through pipe I8, through passage I9, through passage I0, through chamber I2, through passages 23 and 24, past port 25, then through passage 32 to the chamber 33, on the right hand side of diaphragm 34. Valve 54 then travels to the left and admits low pressure from pipe 58 through pipe 56 to passage 55. Valve 54 remains there as low pressure to the left of valve 10, in chamber 68, moves valve 15, closes seat II and opens seat 61. "This drops the pressure in chambers I2 and to that of the pipe 58. As long as valve 54 is open chamber 68 remains at a low pressure.

Testing operation emergency system if called upon will work and it 4 is desired to get back into the primary system then valve 82 is closed by opening the switch controlling the electromagnetic element 11. This puts the system into primary position as a rule.

To make sure of getting back into primary system, lever I I5 is momentarily moved so as to momentarily close passage 55 (equal to closing valve 54). Pressure is thereupon admitted to chamber 68 past check valve I20, thismoves valve 10 to the right.

If it is desired to lock out the emergency governor system then lever H5 is left in its closed position.

If it is desired to lock out the primary system the valve 82 is left in its open position so that valves 54 and I I6 are then both inoperative.

Speed sensing device The speed sensing device has been described in my copending application Serial No. 7 83,071, filed October 30, 1947.

Briefly, the pressure in the inner end of the cylinder 2? equals the pressure in the chamber I2 plus the force exerted by the spring 28, minus the centrifugal force of the weighted piston 26.

Hence, the difference in pressure across the diaphragm 34 is a function of the speed. The motionof the cam en regulates the speed, below which the valve 54 moves to the left, and so brings the emergency system into action in place of the primary governor and primary pump.

What I claim is: r I

1. An emergency fluid fuel control system for a power plant of the type in which fuel flow controls speed, having a source of fuel, a primary fuel inlet passage to said plant, a primary fuel pump located in said passage, a primary governor located in said passage intermediate between the pump and power plant and controlling the flow of fuel from said primary pump to said power plant, an escape passage located intermediate between the pump and the governor, an emergency fuel inlet passage to said plant, an emergency fuel pump located in said passage, an emergency governor located in said passage intermediate between the pump and the power plant and controlling the fiow of fuel from said emergency pump to said power plant, an escape passage located intermediate between the pump and the governor, a control valve located in each escape passage, interconnecting means for the two valves so that if one escape passage is opened the other is closed, automatic means including a third fuel governor having centrifugal means responsive to the speed of the power plant adapted to move the control valves so as to open the escape passage from the primary fuel pump when the speed of the power plant falls below the preselected governed speed and to simultaneously close the escape passage from the emergency fuel pump so as to bring the emergency system into action, immediately the speed of the power plant falls below scheduled speed. I

2. ,A device as set forth in claim 1 in which the third governor includes a rotating element, a cylindrical radial chamber therein, a housing enclosing said element, a piston in said radial chamber, a first valve moved by said piston and controlling the pressure on the inner face of said piston, a first axial passage in said rotating element, a port in said passage controlled by said first servovalve, a source of fluid under pressure in said housing acting on the outer face of said piston, a source of fluid at a lower pressure connected to said first axial passage and, when the port; controlled-by=said firstservovalve is opened ing, a passage from the other side being connected to the second radial passage, a second servovalve connected to the first moving wall, a third chamber associated with the control Valves, a second moving wall therein connected to said two control valves, yieldable means for moving said control valves and said second moving wall into their emergency positions, a passage from a source of low pressure fluidto said third chamber, said second servovalve being located in said passage, means for admitting high pressure fluid to said third chamber to move said second movin wall and the control valves connected thereto to their normal positions in which the escape from the primary fuel pump is closed, yieldable means engaging with the first moving wall, manually operated linkage for simultaneously changing said yieldable means controlling said second servovalve and the primary and emergency governors.

3. A device as set forth in claim 1 in which there are speed responsive means for rendering said control valves inoperative from the time the power plant is first started until it reaches a preselected low speed so that the system remains in its normal position during'the initial stages of the starting operation.

4. A device as set forth in'claim 1 in which there are speed responsive means for rendering said control valves operative whenever the power plant operates above a preselected speed so as to bring in the emergency fuel pump and governor whenever excessive speeds are permitted by said primary governor.

5. A device as set forth in claim 1 in which there is an acceleration responsive device which is connected to the speed responsive device and an acceleration responsive valve which is operatively connected to the acceleration responsive deviceand to the speed responsive device to render the latter inoperative, during acceleration, to bring in the emergency system before a steady speed has been attained.

. 6. A fuel control system for a power plant of I the type in'which fuel fiow determines speed and in which there is a primary fuel pump and a manually controlled primary fuel governor connected thereto driven by said power plant limiting fuel flow, an emergency fuel'pump, a manually controlled emergency fuel governor connected thereto driven by said power plant limiting fuel flow, an escape passage between each pump and each governor, interconnected control valves located in said escape passages for disconnecting fuel flow from the primary governor to the power plant, and for connecting the fuel flow from the emergency governor to the power plant when moved from their normal position to their emergency position, a.speed sensing device also driven by said power plant and operatively con- 6 nected to said valves, said speed sensing device only becoming operative to move said control valves into their emergency position when the speed of the power plant fails to equal that corresponding to that selected by the manual control of said primary fuel governor, a manual control for the speed sensing device, linkage connecting said control to the manual controls of the primary and of the emergency governors so that all three speed responsive. devices are simultaneously and manually adjusted.

7. In combination a rotating power plant of the type in which fuel flow determines speed and which is adapted to'rotate below one critical speed and above another critical speed, a fuel control which comprises a normal and an alternative fuel supply means for supplying fuel to said power plant, two governing means, both acting in response to the speed of said power plant, one to prevent the speedyexceeding the maximum critical speed by restricting the fuel flow, the other to prevent the speed falling below the minimum critical speed by switching from the normal to the alternative and from the alternative to the normal fuel supply, a third speed governing means for the alternative fuel supply to limit the speed by limiting thefuel supply.

8. In combination a rotating power plant of the type in which fuel flow determines speed, a fuel control which comprises two fuel flow systems for supplying fluid fuel to said plant and means acting in response to the speed of said rotating power plant to cut off the one fuel supply system to the power plant as the speed decreases below the predetermined value and to automatically cut in the other fuel supply system to maintain the speed slightly above the predetermined value, two speed responsive governors one acting on each of said two fuel supply systems three manually controlled means, one for selecting the said predetermined limiting value of the speed and two for selecting'the speed at which each of the two governors responds to speed, linkage connecting the three. means together so that they can be varied simultaneously. 9. In combination a rotating power plant of the type in which the fuel flow determines speed and adapted to rotate below one critical speed and above another critical speed, a fuel control which comprises two alternative fuel supply means, three governing means acting in response to the speed of said power plant, one to prevent the speed falling below the minimum critical speed by switching from one alternative fuel supply means to the other, the other two governing means acting one in each fuel supply means to prevent the speed of the power plant exceeding the maximum critical speed by restricting the flow of fuel to the power plant. WILFRED S. BO-BIER, J 3.

REFERENCES CITED The following references are of record in the filev of this patent:

UNITED STATES PATENI 'S 

